We are investigating the molecular basis of insulin activation of monosaccharide transport into rat adipocytes. Current studies focus on testing the hypothesis that insulin causes the transfer of transporter from the microsomes to the plasma membrane and on purifying the transporter from both the microsomes and the plasma membrane. The amount of transporters is being measured by an assay based upon glucose uptake by vesicles with one transporter per vesicle. Purification is being attempted by immunological and conventional procedures.